Dental chair elevator



July 14, 1931. H. E. WEBER DENTAL CHAIR ELEVATOR 3 Sheets-Sheet 1 FiledNov.

July 14, 1931. H E. WEBER DENTAL CHAIR ELE VATOR Filed Nov. 3, 1928 5Sheets-Sheet 2 July 14, 1931. H. E. WEBER DENTALVCHAIR ELEVATOR FiledNov. 5, 1928 3 Sheets-Sheet 3 W 5 W414 d Patented July 14, 1931 entrainerases earns.-

li'ZElflRY E. VI'EBER, 6F CANTON, GHEO, AfSSIG-NGR TO THE VJEBEB DENTALIVL'ANUFACTUR- ING COIiiPANY, F CANTON, I OT-EEO, fr CORPORATION OF OHIODENTAL CHAIR ELEVATOR Application. filed lloven'ibcr 3 1928. Serial No.316,969.

The invention relates to elevators for raisi ng and lowering the seatand attached parts of a dental chair. I

lillrwators for this purpose as heretofore constructed haveincludedchain lifts and fluid dynamic jack lifts. I

It is essentialthat a dental chair elevator bemaintained constantly inthe desired elevated position, without being lowered gradu ally or byjerks, due to the weight of the patient seated on the chair.

It has heretofore been found practically impossible to construct dental.chair elevators, which would not lower gradually or by jerks from anyparticular elevated-position, thereby necessitating frequentreelevations of the same.

Accordingly the principal objects of the present improvements includethe provision of an improved dental chair, elevator adapted forpositively and continuously maintaining the chair seat andattached partsat any desired position ofelevation.

Further objects of the improvements include the provision of an elevatoroperated solely by an, improved fluid dynamic jack, without requiringany chain lifts in conjunction therewith.

Further objects of the improvements include the provision of asimplified and more compact arrangement of the various parts of theelevator, and improvements in the detailconstructionand operation ofthevarious parts. i

These and ancillary objects are attained in the present invention, apreferred embodiment of which ishereinafter set forth in detail, and isillustrated in the accompanying drawings forming part hereof, in whichFigure 1 is a longitudinal sectional view of a preferred embodiment ofthe improved dental chair elevator hereof, ason line1'-1, Fig. 2; I j

Fig. 2, a transverse sectional view there.- of as on line 22, Fig. 1;

Fig. 3, an enlarged fragmentary sectional View as on line 3+8, Fig. '2,illustrating the improved outlet duct for the fluid dynamic jack for theelevator;

Figs, an enlar ed fr a 'tarysectional view as on line 4et, Fig. 1,illustrating the means for adjustably lockingthe chair seat at anydesired position of rotation about its vertical axis;

Fig. 5, an enlarged fragmentary view similar to Fig. 1, distant partsbeing removed,

and portions being broken away for more clearly illustrating the detailconstruction of the improved relief valve for the fluid dynamic jack,and its arrangement with respect to other partsof the elevator;

. Fig. 6, a transverse sectional view thereof as on line 66, Fig.

Fig. 7, another transverse sectional view thereof as on line 7-7, Fig.5; and

,Fig. 8, a ragmentary sectional view of the elevator as on line 88, Fig.2, illustrating one of the yielding stops between two of the elevatorsvsections.

Similar numerals referto similar parts throughout the several views.

The improved dental chair elevator indicatedgenerally at 10, includes abase 11 which is preferably in the form of an upwardly openingcup-shaped reservoir 12 having a. base'flange 13 extending outwardlyfrom its lower end.

Alower tubular elevator housing section 1 f is mounted for rotationabout its vertical axis in the cup reservoir. Upper and lower cylindricbearing abutments are provided at 15 and 16, respectively, between theouter surface of the lower tubular housing section 1st and the innersurface of the tubular side wall 17 of the cup reservoir 12, and thrustbearing abutment is provided at .18 between the lower end of the housingsection 14 and the uppersurface of the bottom Wall 19 of the cupreservoir.

As will hereinafter be set forth in detail, the lower tubular housingsection 14, encloses the operating mechanism of the elevator, andprovides a supportfor all the control levers andpedals, so that thechair seat and other usual parts attached thereto, indicatedfragmentarily at 20, and which are supported through parts hereinafterto be described-in relation to the stationary supporting base 11 whichrests upon the floor.

Preferably vertically coaxial with the lower tubular housing section 14,an improved fluid dynamic jack indicated generally at 21 is mountedwithin the housing section 14 for rotation therewith.

The jack 21 includes a housing and mounting base indicated generally at22, and the base includes a hub 23 from which radiate preferably inopposite directions, an inlet arm 24 having formed therein and mountingthe several parts of the fluid inlet means, and an outlet arm 25 havingformed therein and mounting the various parts of the fluid outlet means,as will be hereinafter set forth in detail.

The hub 23 has an upwardly opening cup recess 26 formed therein, and theupper end of the cup recess is internally threaded to receive and securethe externally threaded lower end of a lower jack cylinder 27 The jackcylinder 27 and the lower housing section 14 are vertically coaxial.

A tubular lower piston 28 is slidably mounted for being raised andlowered in the lower jack cylinder 27, and is externally threaded at itsupper end for carrying an in ternally threaded collar 29.

The collar 29 is externally threaded, and has screwed thereon the upperinternally threaded end of a middle elevator housing section suspendingtube 30, the lower end of which is setzured to a middle elevator housingsection supporting bracket, indicated generally at 31.

The bracket 31 includes a central hub 32 from which radiate a pluralityof supporting arms 33 upon the outer end of each of which is supporteda. lug 34 extending inwardly from a. middle elevator tubular housingsection 35.

The upper end of the lower elevator housing section 14 is preferablyprovided with an inwardly extending flange 36 through which the middleelevator housing section is raised and lowered. V v

Radial movement with respect to each other of the middle and lowerhousing sections 35 and 14 is prevented by providing one 'or morevertically extending guide slots 37 in the one, in each of which slotsis arranged to vertically slide a guide key 38 extending from the other.

The inner surface of the tubular lower. piston 28 forms a cylinder inwhich is arranged to be slidably raised and lowered by the operation ofthe jack, an upper piston 39, of improved construction and arrangementas will be hereinafter set forth in detail, and which mounts at itsupper end an upwardly extending upper elevator housing sectionsupporting strut 40, upon the upper end of which is carried a seat andupper elevator housing mounting disk 41, the seat 20 being provide-dwith a suitable recess for fitting upon the upper surface of the disk41, and the disk 41 being preferably provided with a downwardlyextending tubular flange 42,

which is externally threaded, and which is screwed in the internallythreaded end of an upper elevator housing section 43.

The upper end of the middle housing section 35 is provided with aninwardly directed peripheral flange 44, through which the upper housingsection 43 is raised and lowered.

Radial movement of the middle and upper housing sections with respect toeach other is prevented by providing one or more vertically extendingguide slots 45 in the one, in each of which slots a guide key 46extending from the other, is arranged to vertically slide.

Yielding stop means for limiting the upward and downward movement of themiddle housing section 35 with respect to the lower housing section 14,is provided by one or more rods 47 each vertically slidable in anaperture in a lug 48 extending outwardly from the middle housing section35, and each rod 47 extends above and below the upper and lower surfacesof the lug, and there are preferably removable upper and lower screwheads 49a and 49?), respectively, on the upper and lower ends of eachrod, and a compression spring 50 is interposed between each screw headand the opposite lug surface.

' The upper head 49a: of each rod 47 yield ingly impinges against theinwardly directed 1 flange '36 of the lower housing section 14, foryieldingly limiting the upward movement of the middle housing section.

The lower head 49?) yieldingly impinges against a stop pin 51 extendinginwardly from the inner surface of the lower housing section 14, foryieldingly limiting the downward movement of the middle housing section35.

Similarly, yielding stop means for limiting the upward and downwardmovement of the upper housing section 43 with respect to the middlehousing section 35, is provided by one or more rods 52 each verticallyslidable in an aperture in a lug 53 extending outwardly from the upperhousing section 43, and each rod 52 extends above and below the upperand lower surfaces of the lug, and there are preferably removable upperand lower screw heads 54a and 54?), respectively, on the upper and lowerends of each rod, and a compression spring 55 is interposed between eachscrew head and the opposite lug surface.

The upper head 54a of each rod 52 yieldingly impinges against theinwardly directed flange 44 of the middle housing section 35, foryieldingly limiting the upward movement of the upper housing section'43.

The lower head 54?) yieldingly impinges 'pei'isating connection betweent outer upper end curvedfor fi \vardly opening pivot notch (.39 formedin the outer end of the pump rank 60.

a pump cylinder is mounted, and pump piston 58 is arranged to bereciprocated in the pump cylinder 57 by oscillation of a pump actuatingcrank 60 pi'votally mounts-t on a horizontal stub shaft (31 which issecured in a 'bracket62 extending outwardly from the lower housingsection The crank 80. extends from theshaft 61 through an aperture 83into the interior of the lower housing section i l, and on the outsideof the housing section 14 and connected with the crank 60, an elevatingpedal lever lug aperture in a piston rod bearing lug 66 ez rtendinginwardly from the tubular wall of tnolower housing section, and a comiepump actu- 0 1 r, v. ing tldllri 60 and t is pump piston -.od 60 isprovided by stub link 8? pivotally Secured atone end by a pivot pin (38to the piston rod The stub l i.,.k extends upwardly from the pivot pin68 and has its in a down- T-he upper end of the piston rod has screwedthereon a sleeve 70 upon the upper end of which is provided a shoulder71, and

cylinder.

a compression spring-"72m interposed between the lower face of theshoulder 71 and the upper face of the lug 86, thereby normally urgingthe piston rod and attached piston ugnvardly, ()he or more compressionsprings P I (8 may be interposed between theupper face If the actuatingcrank 60 and the-lower face 4 1., L i 1. Q

of the lug 68 for absorbing slicers of the upward movements of the crank60.

.An inlet duct T5 proviclcs a communication between the cupreservoir l2and the "interior of the pump cylinder 57.

A check valve '76 is provided in the inlet duct and permits oil or otherfluid medium to pass from the reservoir into the pump cylinder butprevents reverse movement there-' from, and the action of the spring'4'" 2 as aforecylinder '27 by a communicating duct 7? formedin the i tarm 24,'and check valve '78 is provided in the communicating duct 77 andpermits the passage of fiuid from the pump cylinder-to the jackcylinder, but pre vents reverse movementthereof.

Atthe lower endof the tubular lower piss ton 28, a plston plug 79 issecured, and has formed therein an aperture 80 of relatively smalldiameter which provides a communicat1on between the interior of the 1ackcylinder 21 and the interior of the tubular lower piston 28. i i i Asaforesaid an upper piston 39 is slid-ably mounted in the tubular lower,piston 28, and

mounts at its upper end, as will now be set' forth in detail, the uppersupporting strut 40.

in the mounting for the supporting strut 40 is embodied an improvedrelief valve 81 for the ack. I v r The upper piston 39 has formedtherein an upwardly opening elongated cylindric socket 82, and the lowerend 83 of the strut 10 is re duced in diameter, and between the endportion 83 of reduced diameter and the main body portion, an outwardlyextending shoulder 84 is formed on the strut.

he reduced end 83 of the strut 40 extends into the upwardly opening cupsocket 82,

'housing section and the shoulder 8 L on the strut 4:0 is seated slideupwardly and downwardly in the bore Above the upper extremity of thestem 87 one or more laterally extending apertures 88 in the strut 40provide outlets from the bore 86, so that any fluid which may be trappedbet *een the extremity of the stem 8'7 and the inner end of the bore,may escape through the outlets 88.

' Longitudinally extending outlet grooves '89 are provided in the outersurface of the strut end 88 and extend upwardly into the main body ofthe strut for forming with the inner surface of the socket 82, outletpassages for fluid which 1s introduced lnto the relief valve chamber 90,which is formed by the inner tubular surface of-thesocket, the uppersurface of the-socket bottom wall 91, and the lower annular eX'tr mityof the strut end '83. The valve stem 87 extends from the strut end 83towards the socket bottom wall 91,

and'a shoulder 92 is formed thereon adjacent the lower end thereof.

Below theshoulder 92, the stem 87 is provided with an enlarged slidingcylindric seat.

93 for a'sleeve 94 which is preferably pro'vid-- ed with hexagonal outersurfaces which form fluid passageways 95 between the outer planesurfaces thereof and the inner tubular surface ofthe socket 82.

A valve closure plug 96 preferably of fibre,

leather, or the like, is fitted in-the lowerend of the sleeve 94:between the lower circular extremity of e cylindric seat 93 and theupper surface ofthe socket bottom w ll g Closure P e 6, he "seat ea, andthaslmg 94 slidable over the continuing cylindric surfaces of the seat93 and the plug 96, provide automatic means for taking up wear on thelower circular end of the plug.

A compression relief valve spring 97 is interposed between the annularextremity of the strut end 83 and the opposite end of the shoulder 92,whereby the closure plug 96 is normally urged towards the upper surfaceof the socket bottom wall 91, for normally closing communication betweenthe valve chamber 90, and a tubular aperture 98 formed in the bottomwall 91.

The aperture 98 provides a communication between the chamber 90, throughan orifice 99 of relatively small diameter, with the interior of thetubular lower piston 28, when the valve stem 87 is raised by upwardfluid pressure which exceeds the downward pressure of the spring 97reacting against the strut end 83.

The strength of the spring 97 is such as will prevent the relief valvefrom operating as aforesaid until the jack has been extended upwardly toits full height.

After the ack has been extended upwardly to its full height the valvestem 87 is raised by continued fluid pressure, permitting all the airand excess fluid to be exuausted from the interior of the jack cylinder21 and the interior of the tubular piston 28.

In the jack outlet arm 25, is formed an improved outlet duct 100, whichincludes an upwardly directed inner portion 100a communicating at 1007),at a substantial level above the lower end 1000 of the inner ductportion 100a, with a downwardly extending outer portionlOOd.

The lower end 1000 of the inner duct portion 100a communicates with aradially ex tending communicating duct 101, the inner end of whichcommunicates with the interior of the ack cylinder 21.

A removable apertured valve seat 102 is preferably provided in the duct101 for cooperation with a self-centering conical head 103 on a valvestem 104, the head 103 being adapted for opening and closing a passageway between the outlet duct 100 and the interior of the jack cylinder21by rotations in opposite directions of a valve screw 105 to which thestem 104 is secured, the valve screw 105 being mounted in an internallythreaded extension of the duct 101.

A pinion 106 is secured to the screw 105 for rotating the same, and thepinion 106 is meshed with an upwardly extending rack 107, which iscarried atthe lower end of a rack mounting rod 108, which extendsupwardly through a suitable bearing aperture in a rack rod bearing lug109 which extends inwardly from the tubular wall of the lower housingsection, and the rack rod 109 is normally urged downwardly by acompression spring 110 interposed between a shoulder 111 at the upperend of the rack rod 109 and an adjustable screw plug 112 which isscrewed. in an internally threaded aperture 113 in the upper end of thelower housing section 14.

The screw 105 has threads of such inclination that when the rack rod 108is pressed downwardly, the self-centering valve head 103 will beadvanced into its seat 102, clos ing the passageway between the interiorof the pump cylinder 21 and the angled outlet duct 100.

For lowering the jack, a lowering pedal lever 114 is pivotally mounted'on a pin 115 secured in the lower housing section 14, and an innervalve opening crank 116 secured to the pedal lever 114 extends throughan aperture 117 into the interior of the housing section 14, where theupper face of the valve opening crank 116 abuts against a pin 118laterally extending from the rack rod 108.

For adjustably locking the chair seat at any desired position ofrotation about its vertical axis, an eccentric 119 is secured at thelower end of a vertically extending countershaft 120 which is journalledwithin the housing section 14, and which is connected at its upper endwith a clamping lever 121 which extends outwardly through an aperture inthe housing section 14. The eccentric 119 preferably is rotatable by theclamping lever 121 in opposite directions to clamp or release flexiblestrip 122 against an inner cylindric clamping surface 123 formed on theinterior tubular portion of the tubular side wall 17 of the cupreservoir 12.

In operating the improved dental chair elevator, constructed andarranged as aforesaid, fluid, preferably oil, is placed in the cupreservoir 12, preferably so that it fills the same to the level of theline A-A.

Oscillation of the elevating pedal lever 64 will then pump the fluidfirst into the interior of the jack cylinder 27 where it willimmediately elevate the lower piston 28, until the middle housingsection 35 has been raised to its extreme height. 1

The fluid will then be forced through the aperture into the interior ofthe tubular lower piston 28, where the upper piston 39 will be elevateduntil the upper housing section 43 has been raised to its extremeheight.

Further oscillations of the pedal lever 64 will only operate the reliefvalve closure plug 96, as aforesaid, to pass the excess fluid outthrough the passageways formed bythe outlet grooves 89 of the strut end83 and the inner surfaces of the socket 82, from which passageways theexcess fluid will drop back into the cup reservoir. 7

Obviously any entrapped air will also be exhausted from the severalcylinders.

The chair seat 20 is positively maintained at its extreme height, or anyintermediate position, if the oscillations of the pedal lever 64 arestopped before the jack has been ele vated to its extreme height.

In order to lower the chair seat 20 all that is necessary is to pushdown on the lowering pedal lever 11 i whereby the seltcentering valvehead 103 will be withdrawn from its seat 102, whereby the fluid willpass out from the several cylinders through the communieating duct 101andinto he angled outlet duct 100 from which it will re-enter the cupreservoir 12.

By forming the outlet duct 100 with the upper end of the inner portion10004, at a substantial level above the lower end thereof, and thecommunicating duct 101, fluid is always maintained within the lowercylinder 27 to the level of the upper end of the duct portion 100a, andas aforesaid the pump cylinder 57 is always chargedwith fluid, wherebythe ack will immediately start to elevate with the first downwardpressure or": the pedal lever 64:.

The chair seat 20, aforesaid, may be maintained at any desired positionof rota- 1 tion about its vertical axis by operation oi upper tubularportion forming a relief chamber therein, a. load carrying strut havinga lower tubular portion supported within the tubular portion of thepiston, an outlet pas sageway communicating between the chamher andfluid introducing means, the bottom wall of the piston having an inletaperture formed therein, a closure member slidably mounted in the lowertubular portion of the strut for movement towardsand from closingposition across the inlet aperture, and i yielding means normallymaintaining the closure member in closing position.

2. A jack for a dental chair elevator and the like, including acylinder, a load sup porting and lifting piston operatively mounted inthe cylinder and adapted to be elevated by the introduction of fluidinto the cylinder, means for introducing fluid into the cylinder, andthe piston having a bottom wall and an upper tubular portion forming arelief valve chamber therein, a load carrying strut having a lowertubular portion supported within the tubular portion or" the piston andforming a passageway located be tween the piston andthe strut andcommunicating between the valve chamber and the fluid introducing means,the bottom wall of the piston having an inlet aperture formed therein, aclosure member provided with a shoulder portion and slidably mounted inthe lower tubular portion of the strut for movement toward and fromclosing position across the inlet aperture, and spring means interposedbetween the shoulder portion of the closure member and the strut fornormally maintaining the closure member in closing position.

A jack for a dental chair elevator and the like, including a cylinder, aload supporting and lifting piston operatively mounted in the cylinderand adapted to be elevated by the introduction of fluid into thecylinder, means for introducing fluid into the cylinder, and the pistonhaving a bottom wall and an up per tubular portion forming a reliefvalve chamber therein, a load carrying strut having at its lower portiontubular walls forming an inner chamber and supported within the tubularportion of the piston, the tubular walls of the strut forming apassage-way located between tne piston and the strut and communicatingbetween he valve chamber and the fluid introducing means, the tubularwalls of the strut being provided with apertures communicating betweenthe strut inner chamber and the fluid introducing means, the bottom wallof the pi ton having an inlet aperture formed therein, a closure memberprovided with a shoulder portion and slidably mounted in the innerchamber of the strut for movement toward and from closing positionacross the inlet aperture, and spring means interposed between theshoulder portion of the closure member and the strut for normallymaintaining the closure member in closing position.

In testimony that 1 claim the above, I have hereunto subscribed my name.

nnnnr E. WEBER.

